The present invention relates to an image control device and a data input device to be used therefor and, more particularly, to a data input device so adapted that a portable coordinate input apparatus can be inserted into and removed from the device, and that coordinate data can be inputted by operating the portable coordinate input apparatus without regard to the state of the portable coordinate input apparatus, that is, an inserted state or a removed state.
As a coordinate input apparatus (data input device) used in connection with an image display device of a personal computer for example, for moving a cursor on the screen of the image display device, a mouse and a track ball have been known.
The mouse or track ball is directly connected to the image display device of the personal computer, to change over details of data displayed on the screen of the image display device and to select various kinds of functions, for instance a spotlight function, a zooming function, and a marker or line function.
As a recent tendency, there has been practiced a so-called presentation (using a large data) in which a speaker explains, to many people, information magnified and projected onto the large data on the basis of the information displayed on the image display device of the personal computer. In such a presentation, the track ball incorporated in a keyboard of the image display device of the personal computer is operated or the mouse directly connected to the image display device of the personal computer is manipulated to move the cursor on the data to change a certain portion of information displayed on the same data or to change over the information to another.
In the above-described known presentation, two persons are generally needed: one for moving the cursor on the display section of the image display device of the personal computer, that is, an operator who manipulates the mouse or the track ball connected to the image display device, and a speaker who explains images displayed on the data. Therefore, if these two persons fail to work in full cooperation with each other, there will occur such a problem that, against the speaker's will, the image displayed on the data makes no change at the preset time of image changeover; the image tends to change at other than the preset time of image change; the cursor position in the image on the screen tends to move out of a proper position; and that it will become necessary to correct the image on the screen to proper one and also to move the cursor to a proper position every time a change is made.
In the above-described known presentation, it is necessary to pay much attention during operation, and also to use much time for operation to display an image of proper information.